Electrical submersible pumps (ESP) are widely used to pump hydrocarbon production wells. A typical ESP has a rotary pump driven by an electrical motor. A seal section, normally located between the pump and the motor, reduces a differential between the well fluid pressure on the exterior of the motor and the lubricant pressure within the motor. A drive shaft, normally in several sections, extends from the motor through the seal section and into the pump for rotating the pump.
ESP's often employ centrifugal pumps having a large number of pump stages. Each pump stage has an impeller that is rotated by the shaft. The impeller has vanes that propel the well fluid radially outward. A diffuser has vanes with passages between that receive the well fluid accelerated by the next upstream impeller and deliver the fluid radially inward to the intake of the next downstream impeller.
Typically, the diffuser vanes have thin, constant thickness walls that spiral inward. However, diffuser vanes that progressively thicken from the outer end to the inner end are known.